On 1/18/07, Jeremy C. Reed < reed@reedmedia.net> wrote:

On Thu, 18 Jan 2007, Dazed_75 wrote:

...
> It would appear that on hplaptop, the name resolution used by ping,
> tracepath, and traceroute is NOT being done through a DNS call. Any clues
> would be appreciated.

ping and traceroute use gethostbyname to do the name lookup. While dig
and nslookup use DNS directly.

Should I have known or been able to learn this easily in some fashion? I had assumed there was a difference but had no clue where to look to find the difference.

When using gethostbyname, it uses nsswitch.conf, host.conf or other
chooser to select which sources for DNS lookups to use and what order to
use.

I thought of nsswitch but it was close to the end of the meeting and had no time to read the man page. I will do so. Actually I remembered it affected lookup sequence from my job back in the 80-90's but not how or how to use it.

Commonly your local file /etc/hosts is used first and then normal DNS
lookups is used if needed. Your normal DNS lookups are controlled by
/etc/resolv.conf.

So start by looking at /etc/hosts and then /etc/resolv.conf.

We did check /etc/hosts and cleaned it up and later rebooted. I was not sure if the file might be cached or how to force a re-read so the reboot was to ensure that. I did not think to check /etc/resolv.conf since we were able to surf the net. But now I think on it maybe we were bypassing dnsmasq on the router and going directly to the ISP dns servers. I will ask the owner to check this. I would have thought though that /etc/resolv.conf would have been updated as a result of the DHCP request when the system was rebooted. Am I wrong there?

Jeremy C. Reed
---------------------------------------------------
PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us
To subscribe, unsubscribe, or to change you mail settings:
http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss